Adjustable boring head for continuous mining machine



F. CARTLIDG E May 3, 1955 ADJUSTABLE BORING HEAD FOR CONTINUOUS MINING MACHINE Filed Aug. 26, 1953 5 Shets-Sheet 1 IN VEN TOR.

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' ADJUSTABLE BORING HEAD FOR CONTINUOUS MININGMACHINE Filed Aug. 26, 1953 3 Sheets-Sheet 2 22b Fig-2 IN VEN TOR.

y 3, 1955 F. CARTLIDGE 2,707,626

ADJUSTABLE BORING [HEAD FOR CONTINUOUS MINING MACHINE Filed Aug. 26, 1953 3 Sheets-Sheet 3 m m U E (is a 8 2 R0 f" R: 96 Z z 5%: 'i? m g I gr, CR 8 g INVENTQR.

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s i\\ I fATioRm-w 2,797,626 Patented May 3, 1955 "fice ADJUSTABLE BORENG HEAD FOR CONTINUOUS MINING MACHINE Frank Cartiidge, Chicago, llll., assiguor to Goodman Manufacturing Company, Chicago, Ill., a corporation of Illinois Application August 26, 1953, Serial No. 376,652

4 Claims. (Cl. 262-4) This invention relates to improvements in mining machines of the boring type wherein at least two boring heads, each having arms with forwardly projecting cutter bits, are arranged with their arms in side-by-side overlapping relation to out two contiguous bores. Such machines are usually also provided with horizontally disposed cutter chains or other auxiliary cutting devices at the floor and roof to smooth off the triangular cores left between the adjacent boring heads so that the resulting bore is generally oval in cross section.

Machines of the general type above described have heretofore been provided with means for extending or retracting the extreme outer set of cutter bits at the ends of the boring arms, in order to vary the effective cutting diameter of the boring heads in accordance with the height of the coal to be cut. Normally, this height is subject to some variation and, sometimes, there are cases when it is not desirable to mine the full seam thickness. For example, in a mine Where the seam is nominally seven feet thick, there will he places Where the seam may be as little as six feet thick. Again, there are instances where hard, sulphur-bearing occlusions are in the coal (or other mineral) near the roof or floor levels. These occlusions are very hard on bits and are preferably not mined so the mining machine will be adjusted to a smaller diameter to avoid them. Also, when backing out of a room, when being trammed from one place to another, when avoiding a squeeze between the roof and floor, the radial arms will be retracted to some diameter less than their maximum working diameter. Thus, for best operation, the radial arms must be capable of working in a number of positions between maximum and minimum diameter positions.

Among the objects of the present invention is to provide power mechanism for expanding or retracting, in unison, the ends of the radial cutter arms of each boring head in accordance with mining conditions and needs of the mining cycle.

A further object of the invention is to provide limiting means for adjusting the amount of expansion or retraction of the ends of the arms, and for locking said ends in various adjusted positions, to protect the expanding and retracting mechanism from stresses resulting from thrust reactions during actual mining operations.

Other objects and advantages will appear from time to time as the following description proceeds.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure l is a front view, looking from the mine face, of a boring head assembly made in accordance with the present invention, with some parts omitted and other parts shown in section;

Figure 2 is an enlarged sectional View taken on line IIII of Figure 1;

Figure 3 is a detail end view of one of the radial arms, taken on line III-III of Figure 2;

Figure 4 is an enlarged detail section similar to Figure 2, but also showing, in additional detail, the power mechanism for varying the length of the radial arms;

Figure '5 is a detail perspective view, showing one of the thrust collars, in unassembled condition, used for locking the end of a radial arm in a predetermined position.

Referring now to details of the embodiment of my invention illustrated in the drawings, the same is shown as applied to a single boring head indicated generally at 10, having three radial boring arms indicated generally at 11, 11, 11. It will be understood that the boring head may have only two arms arranged diametrically from each other and that, in practice, the boring head may be arranged in side-by-side relation with a similar head, with the arms rotating in overlapping non-interfering relation. Such boring head arrangements are well known in the art and further details need not be shown nor described, since the present invention is directed more specifically to the construction of a single boring head of the radially expansible type.

The boring head 10 is mounted on a main frame 21 of a suitable mobile vehicle (not shown), which frame includes at its front end a housing .211: having a forwardly projecting generally cylindrical hollow shaft 22 rotatably mounted therein by rear bearings 22a and front bearings 22b. The rear bearings 22a are supported in a hollow base 22c formed integrally with the housing 21a.

A hub 25 is splined on the front end of shaft 22 and has a plurality (herein three) of hollow radial arm sections 26 formed integrally therewith at equally spaced angles to each other.

Each of the arm sections 26 has a movable section 27 telescopically fitting in the end thereof. In the form shown herein, said telescopic sections are generally cylindrical having inner end portions 27a splined in their respective arm sections and outer end portions 27b formed with a plurality (herein three) of annular grooves 27c thereabout, for receiving a locking ring, as will hereinafter more fully be described. Each of said telescopic sections may also have an intermediate annular bearing collar 27d (see Figure 2) having a sliding fit in the end of its hollow arm section, and carrying a suitable sealing ring 27c for keeping dust and dirt out of the hollow hub.

Each of the radial arm sections 26 has a plurality of forwardly projecting cutter bit supports 28 mounted thereon, said cutter bit supports carrying a plurality of cutter bits 28a, 28a along their outer ends in the usual manner for cutting a plurality of circular kerfs in the coal face. The outermost end of each telescopic section 27 has a similar forwardly projecting cutter bit support 29 with cutter bits 29a thereon for cutting the outermost kerf. Scoop plates 30 may also be mounted, as usual, on the end of each radial arm, in the form shown herein said plates being mounted on the end of the telescopic sections 27. A center bit 31, tapered near its inner end, projects from the front end of the hub, concentric with the latter. Since the cutter bit supports, the scoop plates, and the center bit are well known in the art, they need not be further described, as they form no part of the present invention.

Referring now to the means for extending or retracting the telescopic sections, it will be seen from Figures 2 and 4 that the shaft 22 has a bore 32 at its front end, in which is fitted a cylindrical slide 33. Umbrella type links 33:: are pivoted at their inner ends to said slide and at their outer ends to each of the telescopic sections 2'7. Axially aligned with the shaft 22, but fixed at its rear end to the frame housing 21a, is a hydraulic cylinder indicated generally at 34, herein consisting of an outer shell 34a and an inner shell 34b. Said inner shell has a piston 35 therein, with a piston rod 36 connected to the slide 33 through a rotatable connection comprising a two-way thrust bearing assembly 37 of conventional construction secured to the rear end of the slide by a retaining plate 37a.

The cylinder 34 is double-acting; in the form shown, fluid pressure is admitted through line 38 and bore 38a to the rear end of the cylinder, and through line 39, communicating with the space between the cylinder shells 34a and 34b to inlets 39a at the front end of the cylinder. Fluid pressure is supplied from a suitable source under manual valve control (not shown).

The use of the rotary bearing connection 3! permits the cylinder 34 and its piston rod 36 to be made stationary with respect to the main frame, while the shaft 22 and the slide 33 rotate, thereby eliminating complicated rotating pressure joints between the cylinder and the pressure lines 38 and 39.

The shaft 22 has a spur gear 46 splined thereon and driven through a pinion 41 on shaft 42, from a suitable source of power, to rotate the boring head.

As seen in Figures 1, 2 and 5, means are provided for locking or limiting the telescopic arm sections 27 against inward movement in a plurality of selective positions for cutting bores of difierent diameters. Said locking means consist of a split collar 45 made up of hales 45a and 45b normally held together by bolts 46. The collar has an inwardly projecting annular rib 47 adapted to be fitted selectively in one of the annular grooves 270 formed about the end portions 271: of the telescopic sections 27. In operation, reaction from the mine bore exerts an inward thrust on the telescopic arm sections 27, so as to maintain each collar in engagement with the adjacent end surface of the hollow arm 26. Accordingly, adjustment of the several collars in the same groove position on all the arms will ensure cutting of the bore at the desired diameter, and protect the cylinder and linkage mechanism from the reaction exerted on the telescopic sections during mining operations.

Although I have shown and described certain embodiments of my invention, it will be understood that I do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a mining machine including a frame, a hollow drive shaft journalled in said frame, a boring head on said shaft having a plurality of radially extending cuttercarrying end sections telescopically mounted thereon, and means for telescopically moving said end sections relative to said arms, comprising a slide movable axially along said shaft, a pressure cylinder having its inner end fixed on said frame at the rear end of said shaft, a piston rod in said cylinder extending axially of said shaft and having a rotatable bearing connection with said slide, and linkage means connecting said slide with the inner ends of each of said telescopic end sections for moving the latter radially relative to the axis of said boring arms in response to fluid pressure in said cylinder.

2. A mining machine structure in accordance with claim 1, wherein the cylinder extends into the rear end of the hollow shaft, and has fluid connections through a rear end support on the frame, alfording double-action for either extending or retracting the telescopic end sections.

3. A mining machine structure in accordance with claim 1, wherein the radial arms are hollow and the end sections are guided therein for extensible movement.

4. A mining machine structure in accordance with claim 3, wherein each of the telescopic sections has a plurality of exterior grooves formed adjacent its outer ends, and a detachable collar having selective fitting in one of said grooves is provided for abutting engagement with its respective arm, to limit inward movement of said telcscopic end section relative to the latter.

References Cited in the file of this patent UNITED STATES PATENTS 241,483 Faught May 17, 1881 314,926 Freider et al. Mar. 31, 1885 1,335,723 Campbell Apr. 6, 1920 1,371,224 Campbell Mar. 15, 1921 1,603,621 McKinlay Oct. 19, 1926 1,726,963 McKinlay Sept. 3, 1929 OTHER REFERENCES Coal Age, May 13, 1926, pp. 667670. 

